Struggling to lose or gain weight? IIFYM is what you need!

Are you constantly switching from one diet to another with no lasting result? Well, look no further! The answer is IIFYM. Before I explain exactly what it is I think it is important that you know a little basics about food.

Food is energy. We need food in order to do anything and we measure the food we eat as our calorie intake. The energy we use can be seen as our calorie expenditure.

The reason that you gain weight is that your calorie intake is more than your calorie expenditure. In other words you eat more food than the energy you use.

So, if your goal is to lose weight you can either: Reduce your calorie intake (consume less food) or you can increase your calorie expenditure (become more active)

On the flip side when you lose weight it is because you eat less food than the energy that you use.

If your goal is to gain weight you can either: Increase your calorie intake (eat more food) or you can reduce your calorie expenditure (be less active).

What happens when we consume the exact amount of calories that we used on a given day? You guessed it! You will neither lose/gain weight. This is known as your maintenance calories.

Later in the post I will help you to work out your maintenance calories.

What is IIFYM?

IIFYM – If It Fits Your Macros. It is a way of tracking your calories and your macros.

What are macros? It is a shorthand used for macronutrients. It is nutrients that we need on a large scale and includes:

Carbohydrates, Fat/Lipids and Protein.

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Micronutrients are nutrients that we need in smaller doses. Some examples of micronutrients are: Iron, Calcium, Vitamins, Potassium, Magnesium etc.

For the purpose of weight loss/gain we won’t focus on micronutrients, but be sure to have a diet that includes the needed micronutrients to make sure your body stays healthy.

Why does IIFYM work?

The reason most diets don’t work in the long term is that there might be an initial reduction in calorie intake, but after you are done with the diet you return to your normal eating patterns. Which is the reason that you started the diet in the first place.

With IIFYM you are in control of what you eat. You can still eat what you want, although I do recommend that you make sure that about 70% of your diet is composed of wholesome, healthy food.

You keep track of the exact amount of calories that you take in per day. So you know exactly what is going into your body and whether you are in line with your goals or not.

How to use IIFYM?

Working out your desired calories based on weight goals:

  1. Figure out you basal metabolic rate (BMR).

This is the number of calories you need in order to keep your body functioning at rest (all the vital functions of your body, like your heart, lungs, etc. excluding movement).

Owen formula to work out your BMR:

MEN: BMR = 879 + 10.2 (weight in kg)

WOMEN: BMR = 795 + 7.2 (weight in kg)

There are different formulas that you can use, but this one is pretty simple. If you want to use an online calculator you can go here.

  1. Multiply your BMR with an activity factor to estimate your maintenance calories.

Do not lie to yourself here, have a good look at how active you are, and use one of the following factors.

BMR x 1.2: Sedentary (Minimum activity. Sitting most of the day, no exercise etc.)

BMR x 1.3-1.4: Lightly Active (Exercise 1-3 days)

BMR x 1.5-1.6: Moderately Active (Exercise 4-5 days a week)

BMR x 1.7-1.8: Very Active (Training hard for a specific sport or purpose 5-6 hours a week)

BMR x 1.9-2.2: Extremely Active (Endurance training or athlete who spends 10 or more hours training a week)

Again if you want to use an online calculator you can go here. If you use this one you do not have to use the previous one.

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  1. Adjust you calories according to your goals.

If your goal is to gain weight:

Maintenance calories + 250 calories

It’s up to you how much you want to add but starting small is better to avoid piling on unnecessary fat.

If your goal is to lose weight:

Maintenance calories – 250 calories

Again I’d say start small and go from there. Observe how you are feeling. I made the mistake of cutting too many calories and I felt very inactive, I had no energy and no desire to do anything.

  1. Adjust your calories:

Use a body scale and weigh yourself daily. Ideally in the morning after a bowel movement. Write down your weight. This way you will see when you are not gaining/losing weight anymore and then add/reduce calories accordingly or be less/more active.

All about macros!

Now that we have our target/goal calories we must discuss the calories per gram contained in the different macros and calculate the ratios of the macros.

Calories per macro:

Protein – 4 calories per gram

Fat – 9 calories per gram

Carbohydrates – 4 calories per gram

Alcohol – 7 calories per gram

Ratio of macros:

Let’s use the following scenario to help you understand how to apply the information. A person that weighs 220 pounds (100 kg) and has a target/goal calorie value of 3098 per day.


1 gram per pound of bodyweight is generally fine to use.

1 x 220 pounds = 220 grams

220 grams x 4 calories = 880 calories of protein

3098 – 880 = 2218 calories remaining for both fats and carbohydrates.


30% is the value I usually use. This can be less, anywhere between 20-30% is a good range to use.

3098 x 30/100 = 930 calories

930/9 = 103 grams of fat


Whatever calories you have left goes to your carbohydrates.

3098 – 880 – 930 = 1288 calories

1288/4 = 322 grams of carbohydrates.

This is a nice base to work with. Observe how your body is feeling. Test different ratios and again observe how you are feeling.

Fiber is also very important. A general rule is to consume 8-12 grams of fiber per 1,000 calories you consume.

Tracking your calories and macros:

This is really a simple process. All you have to do is weigh your food and enter it into an online calorie counter or a phone app. For the first couple of weeks weigh everything you eat. After a while you will be able to eyeball the weight of the food you eat. You also have the option to work with the volume of foods, but weighing is easier for me.

If you want to be precise keep on weighing all of your meals.

In my opinion the best calorie counter to use is myfitnesspal. They also have an app that you can download in the app store.

For a beginner’s tutorial on how to use myfitnesspal you can go watch Remington James’ video here.   

Benefits of IIFYM:

You must still maintain a healthy and wholesome intake of food but you can go have a burger at your favorite restaurant and enjoy a beer (or whatever you drink) as you are tracking your calories.

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This way you will still be able to enjoy what life has to offer and at the same time meet your nutrition goals.

What if you ate too much on Tuesday? All you have to do is reduce your calorie intake throughout the rest of the week to make sure you meet your weekly calorie goals.

This is definitely the best way to monitor your nutrition in my opinion. You will know exactly what you ate and when you ate it and you will know the exact amount of macros and calories you consume.

I hope you have enjoyed this post about IIFYM and found it to be very practical and informative. If you have a question leave a comment down below and I will definitely get back to you.

Remember that you are responsible for the food you choose to consume. Of course, training goes hand in hand in creating your goal body, and if you would like to know more about improving your training click here.

You have the power to change your body for better or worse.


I am passionate and fascinated about how the human mind works and why we do what we do. I want to share what I have learned with others while also helping them to achieve a body they are proud of.

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1 Response

  1. Chris says:

    This is such a great post! I do really great with getting my workouts in, but I know my body could respond to them so much better if I took the time to properly fuel before and after a workout!

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